The water felt surprisingly chilly, and for a moment I hesitated before completely immersing myself in the cool, clear water. More a creek than a river this time of year, this crossing of the West Fork San Gabriel River was at mile 17 of the 2012 Mt. Disappointment 50K. At 2760', it's the lowest point on the course and marks the beginning of the tough 5.4 mile climb up Edison Road to Shortcut Saddle (4790').

Edison Road (FS Road 2N23) zigzags up an exposed, south-facing chaparral slope. The climb is warm on the coolest of days -- today it was going to be torrid. Southern California was locked in the grasp of a record-setting, multi-day heat wave. During the week I'd taken a thermometer on a run and measured a temperature of 107.6°F on a breezy day at Ahmanson Ranch. All week I'd been checking the computer weather models and watching the temps in the San Gabriel Mountains, hoping for a break in the weather. Nada. The day before the race the "in the sun" temps at the Clear Creek RAWS, near the race course, reached a blistering 120°F.

The performance hit from running in the heat is similar to running at higher elevation. Acclimatization helps, but hot weather reduces performance. The following is from Daniels' Running Formula:

"You can’t perform as well in a distance race in the heat as you can in a cooler environment... As soon as the body starts to heat up, blood is diverted to the skin, where cooling (through evaporation of sweat from the skin’s surface) takes place. A greater portion of the body’s blood volume is at the body’s surface to facilitate cooling, leaving less blood available for carrying oxygen to the exercising muscles. In effect, to prevent overheating, the body reduces the amount of blood available to enhance performance."

I didn't catch the late evening update of the forecast when the 20% chance of showers and thunderstorms in the San Fernando Valley was extended into Saturday morning, but the raindrops on my car and the towering cumulus to the west were pretty good clues that I might get wet on my run.

A friend was doing the Baldy Run to the Top course, but one week out from the Mt. Disappointment 50K I'd opted for something a little more moderate -- a 13.1 mile keyhole loop through Cheeseboro Canyon from the Victory trailhead at Ahmanson Ranch. The Mt. Disappointment course has a lot of elevation gain, and today the 1,300' of gain/loss on the Cheeseboro Canyon run sounded a lot better than the 3900' gain/loss on Baldy!

It sprinkled on and off as I made my way out East Las Virgenes Canyon and up Las Virgenes Canyon. A little while after turning onto the single track that leads to Shepherds' Flat, the rain drops grew bigger and soon after I was running in a shower.

It is a rare thing to run in the rain on an August morning in the Simi Hills. It added a dimension not often found here in Summer, dampening sun-parched chaparral and refreshing its scents, smells and colors.

I reached the junction at Shepherds' Flat and turned south onto the Cheeseboro Canyon Trail. As if signaling my turn, thunder rumbled through the hills behind me. It sounded like the active cell was a few miles to the north -- probably over Simi Valley. The running in upper Cheeseboro Canyon was outstanding. I was there early and the main wave of cyclists were still working their way up the canyon, after waiting for the Cheeseboro parking lot to open.

The rolls of thunder were now growing more distant, and from time to time a shaft of sunlight would break through the clouds. Along the trail laurel sumac and Datura had captured small puddles of water in the V of their leaves, and occasionally the sun would glint from one leaf and then another.

With the showers and clouds, the temperature was almost chilly. If only we could have cool weather for Mt. Disappointment! Not likely -- the MRF medium range computer model was forecasting a heat wave in Southern California over the next several days. Inland temps were forecast to peak race day (Saturday) with temps at the lower elevations of the San Gabriel Mountains reaching around 100 degrees. Some clouds and an afternoon thunderstorm were a possibility, but the degree to which monsoonal moisture would be pushed up into Southern California was a big question mark.

Update Wednesday, August 8, 2012. Measured some temperatures on a run at Ahmanson yesterday. Temperatures generally ranged from about 103°F to 108°F. There was a pretty good breeze with a lot of mixing. These were temps out in the open a few feet off the ground. Even with the breeze ground temps in full sun were over 120°F. Today's 12z and 18z NAM shows valley temps peaking on Friday, with a little cooling on Saturday. An increase in monsoonal moisture is forecast into Saturday above about 10,000', but dewpoints/humidities below that level remain relatively low. Hot temperatures (95°F to 105°F) are still forecast for Saturday in the lower elevations of the San Gabriel Mountains.

Update Tuesday, August 7, 2012. Yesterday Woodland Hills tied the record high temperature for the date of 108°F. This morning's NAM weather model forecasts warming to continue inland through at least Friday, and this morning's MRF still has the hottest inland temps on Saturday. The amount of monsoon moisture is still uncertain. The high pressure system is in a position that could transport moisture into Southern California, but so far the models are not forecasting a strong monsoonal flow.

This loop is a variation of the Cottonwood Pass - New Army Pass loop. Starting and ending at Horseshoe Meadow, much of the route is the same except for the pass that is used to descend into Cottonwood Lakes Basin. The following map shows GPS tracks of the routes using Army Pass (red) and New Army Pass (blue).

From a trail running (without an ice axe) point of view the Army Pass option should only be considered after most of the Sierra snowpack has melted and the trail over the pass is free of snow. This can be very late in the Summer or in some Summers not at all. Low snowpack years are the best bet. Depending on the snowpack and time of year both Army Pass and New Army Pass can be impassable without special mountaineering equipment, skills and experience.

Built in 1892, the 120 year old trail over Army Pass is not maintained. It is most often used by those climbing Mt. Langley. Because of its northeasterly aspect there is often snow/ice on the trail and the area is prone to rockfall. The upper part of the trail follows a boulder and rubble-strewn shelf along a precipice. While the path is well-used, careful attention is required. Here's a photo looking up the path toward the pass and a similar photo from June 2007.

Once off the pass the running in upper Cottonwood Lakes basin is outstanding. The trail circles through the talus over to the north (far) side of Cottonwood Lake #4 -- the lake immediately below the pass -- and then continues across a land bridge between Lake #4 and #5 to the outlet of Lake #4. From here the trail drops down to Lake #3 and after about 2.5 miles of superb running meets the trail coming down from New Army Pass.

The approximate length of the loop is about 20 miles, with an elevation gain/loss of about 3250'. Here's a Google Earth browser view of my GPS track of the loop. Placemark locations are approximate.

These young-appearing bigcone Douglas-firs along the Valley Forge Trail are probably older than they look. According to the Forest Service Silvics Manual, Volume 1: Conifers, saplings may be only 2 ft. tall when 40-50 years old and as old as 70 years when they break through the oak overstory.

The bigcone Douglas-fir is a very resilient tree that is remarkably fire tolerant. It can lose virtually all of it foliage to a fire, appear to be beyond the point of recovery, yet survive and regenerate its foliage. Fire-scarred bigcone Douglas-firs have been used to analyze fire history and regimes.

The photograph on the left is of a bigcone Douglas-fir along the Valley Forge Trail that was burned in the 2009 Station Fire. Here is a closer view of the same tree showing how new foliage sprouts from buds along its limbs and trunk.

The Valley Forge Trail is in the canyon of the West Fork San Gabriel River in the San Gabriel Mountains near Los Angeles. It connects the Gabrielino Trail to Eaton Saddle on Mt. Wilson Road. The trailhead for Mt. Lowe Truck Trail is at Eaton Saddle.

Somehow I've managed to avoid reading any hype, advertising or reviews related to the Salomon XT Wings 3. To date I've put about 60 miles on my first pair -- including a couple of 16-20 mile runs in the San Gabriel Mountains. Following are my first impressions of this $140 shoe.

Altogether I've run in about 20 pairs of XT Wings and XT Wings 2. I run almost exclusively on trails. Racing is not my focus, but I run a few ultras each year, as well as several 15K-30K races. Most weekends I do a longer run in the mountains. I have a D-width, neutral, high-arched foot. My foot strike varies, but tends to be more mid-foot than on the heel.

Wow, was I surprised when I pulled these shoes out of the box! Rather than a tweaked version of the XT Wings 2, the XT Wings 3 looked like a completely new shoe -- kind of a blend of the Salomon SpeedComp, SpeedCross and XT Wings 2. My overall impression was one of increased precision, performance and versatility.

After weighing the shoes (25 oz/pair - size 9), I compared the outsoles. Big changes here. Gone is the wider heel and platform that has characterized the XT Wings line. The sole now sports chevron-shaped lugs, similar to the SpeedCross. In my opinion this is a more versatile design, and traction should be improved on a variety of surfaces. The lugs should also help forefoot cushioning. I also noted the density of the heel strike pad appears to have been increased.

Twisting the shoe along its length, the XT Wings 3 appeared to be stiffer torsionally. There's a new toe cap, and since I've already kicked a couple of rocks, I can attest that it is more protective than earlier versions. Another change is the heel cup is now more anatomically shaped.

The fit of the XT Wings 3 is comfortable, but more snug than the XT Wings 2. Perhaps because of my high-arched foot, the reduced mid and forefoot volume in the XT Wings 3 is more evident. It fits me more like the SpeedComp or SpeedCross. I have to carefully adjust the speed-lacing to ensure there is not too much pressure on the top of my foot. The difference in the volume is particularly noticeable after running in the XT Wings 3 several days and then switching back to the XT Wings 2.

So how did the XT Wings 3 run? Very well! Other than having to carefully adjust the speed-lacing, I had no issues with the shoe. Cushioning, comfort, traction and protection all seemed good. It's difficult to evaluate in just a few runs, but the more narrow platform of the XT Wings 3 may make it a little less roll resistant on uneven surfaces than the XT Wings 2.

There are always trade-offs in design, and runners are VERY particular about their shoes. One shoe cannot be ideal for all runs and all runners. I have to put more miles on XT Wings 3 to see where it works best for me. Based on my initial impressions, I think I would tend to use the XT Wings 3 on faster paced runs where precision and performance are important. I still have several pairs of the XT Wings 2, and the longer the run, the more likely I will be to use the XT Wings 2 -- a shoe that has worked exceedingly well for me.

The photograph above is of telescope "E1" of Georgia State University's six telescope CHARA optical/infrared interferometric array on Mt. Wilson. The long tubes extending from the telescope enclosure are vacuum light tubes. These carry light from each of the six one meter telescopes to a facility where the beams are processed and combined. The photograph is from a recent run on the Mt. Wilson Rim Trail.

Other things being equal, a telescope's ability to discern detail is determined by its aperture. In a conventional telescope the aperture is the width of the main optical element. The majority of telescopes used by amateurs have apertures well under 0.5 m. Larger professional optical telescopes can range from a couple of meters up to about 10 m. The Hooker telescope on Mt. Wilson has an aperture of 2.5 m and the 200" Hale telescope on Mt. Palomar about twice that. Hubble's primary mirror has a diameter of 2.4 meters.

The benefit of a telescope array is that when the light from two telescopes is combined, the combined instrument's ability to discern detail -- its resolving power -- is nearly the same as a telescope with an aperture equal to the distance between the telescopes. This distance is termed a baseline. The Y-shaped CHARA Array has 15 baseline configurations ranging from 31 to 331 meters.

The CHARA Array's large effective aperture, the successful application of leading edge optical technologies, and exceptionally steady atmosphere over Mt. Wilson have produced a number of astronomical imaging "firsts," including an image of the surface of a main sequence star (Altair) and images of an interacting binary star system with a suggestion of mass transfer between the pair.

The Altair imagery above is from a University of Michigan News Release that accompanied the publication of the paper "Imaging the Surface of Altair" by Monnier et al., 2007, Science.

The gate to Skyline Park on Mt. Wilson doesn't normally open until 10:00 a.m., so for Saturday's run we parked in a large turnout along the loop road downhill from the gate. A trailhead that accesses the Kenyon Devore Trail is just downhill from the turnout, and a few yards down the trail is the lateral trail to Skyline Park. The Rim Trail trailhead is in Skyline Park along the service road that leads to the observatory grounds. This Observatory Pamphlet (PDF) includes a map that shows its location.

So we're about to start the run, and I'm going through the routine of last minute checks. Everything looks good so I lock the car and -- nothing happens. Where's the familiar single beep? I try again... Nothing.

Ah technology! It doesn't take long to figure out that those giant transmitters towering above me are jamming my smart key. OK, I want to get running, but I also want to be sure I'm going to able to start the car when we get back. Fortunately, the key system has an emergency mechanical key to get in the car, and then there's a procedure to enable the car to detect the smart key. The procedure works, and after (mechanically) locking the car we're off and running.

I've parked in Skyline Park several times without having a smart key problem; however a few years ago I did have a problem with a GPS watch getting a lock on satellites at the start of a Mt. Disappointment race. That hasn't happended with my current Garmin watch, which has much better satellite acquisition and sensitivity.

I guess whatever lobe of RF was interfering with the key changed shape or position, because when we got back to the car at the end of the run the smart key worked fine!